Cryogenic freezing of food products has become more and more frequently used and has become particularly useful for freezing food products having surface characteristics which should appear aesthetically attractive following freezing. Because cryogenic freezing must compete with other types of freezing in the economic marketplace, it is important that cryogenic freezing be carried out in a particularly efficient manner. One way of improving efficiency is to incorporate the ability to supply the cryogenic refrigeration to the food product in a manner which matches the rate at which the food product can accept such refrigeration and give off its internal heat. For many such products, the rate at which the product can accept cooling is the greatest initially, and accordingly the freezing of such products can be most efficiently carried out using apparatus which initially extracts heat therefrom at a very fast rate. Side benefits of achieving such efficiency include the preservation of texture and prevention of dehydration.
There are also needs for apparatus which can freeze discrete particulate material as opposed to the freezing of hamburgers or the like which are fashioned into patties and generally maintained in an ordered array upon a conveyor belt or the like. As in the case of handling all food products, cleanliness if important, and the ability of apparaus to be cleansed in an efficient manner at the end of a particular operation also constitutes an important feature. Although many versions of apparatus have been developed for freezing food products of this general type, such apparatus have met with less than total success, and it is desirable to provide cryogenic freezing apparatus having improved features and which can freeze food products more efficiently than apparatus currently in use.